From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E42BCA0EE6 for ; Thu, 14 Aug 2025 19:05:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7F92D9001CA; Thu, 14 Aug 2025 15:05:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7A945900172; Thu, 14 Aug 2025 15:05:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69B209001CA; Thu, 14 Aug 2025 15:05:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 55DE4900172 for ; Thu, 14 Aug 2025 15:05:51 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 209455B172 for ; Thu, 14 Aug 2025 19:05:50 +0000 (UTC) X-FDA: 83776292460.24.10F4F4D Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by imf16.hostedemail.com (Postfix) with ESMTP id CAA7F180006 for ; Thu, 14 Aug 2025 19:05:47 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=csgroup.eu; spf=pass (imf16.hostedemail.com: domain of christophe.leroy@csgroup.eu designates 93.17.235.10 as permitted sender) smtp.mailfrom=christophe.leroy@csgroup.eu ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1755198348; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YHyGC2tklvgN0REkQ0ldTWNmLFHcFMgQsr/26aDn6pU=; b=ZCbjyhRQugnH6HMDsQvENMeXYMFlgl8BwwDBOdGvd5q6JHB/jXm5rIdUHrEnaZkWLa/m+q nlogx2Ms4Nt/qDYWB8iXwdPcIWY1s2SM+NiAqozgdYvgd5L+OkDNl3yU/9Bp94GkPTy5uK aCrnldqRXoxW9ZJ57AMf9k6SpFr7B6I= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=csgroup.eu; spf=pass (imf16.hostedemail.com: domain of christophe.leroy@csgroup.eu designates 93.17.235.10 as permitted sender) smtp.mailfrom=christophe.leroy@csgroup.eu ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1755198348; a=rsa-sha256; cv=none; b=MX2IHBvyZjYCvXdSuFpxfLSMMe4eMGr/yj+NMJ6Ghpgiskkj5ZA7CNbesh1gRJvUo/54Uu o12C9qKY4JH/zCMDM3k1H4qXJM3B43H86/cO7MBcsJvue37QT1hdU88hBTrI1N4bwRRHZ/ 9vjIxImgMl75VQx9jKwKyubCSU533Zg= Received: from localhost (mailhub4.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4c2vpK65M9z9sSH; Thu, 14 Aug 2025 21:05:45 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ZPu83EvDtL2B; Thu, 14 Aug 2025 21:05:45 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4c2vpK3P9dz9sSC; Thu, 14 Aug 2025 21:05:45 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 16AD08B764; Thu, 14 Aug 2025 21:05:45 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id v81OkG88qzZ0; Thu, 14 Aug 2025 21:05:44 +0200 (CEST) Received: from [192.168.235.99] (unknown [192.168.235.99]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 592BF8B763; Thu, 14 Aug 2025 21:05:43 +0200 (CEST) Message-ID: Date: Thu, 14 Aug 2025 21:05:42 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 00/16] dma-mapping: migrate to physical address-based API To: Leon Romanovsky , Marek Szyprowski Cc: Jason Gunthorpe , Abdiel Janulgue , Alexander Potapenko , Alex Gaynor , Andrew Morton , Christoph Hellwig , Danilo Krummrich , iommu@lists.linux.dev, Jason Wang , Jens Axboe , Joerg Roedel , Jonathan Corbet , Juergen Gross , kasan-dev@googlegroups.com, Keith Busch , linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nvme@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-trace-kernel@vger.kernel.org, Madhavan Srinivasan , Masami Hiramatsu , Michael Ellerman , "Michael S. Tsirkin" , Miguel Ojeda , Robin Murphy , rust-for-linux@vger.kernel.org, Sagi Grimberg , Stefano Stabellini , Steven Rostedt , virtualization@lists.linux.dev, Will Deacon , xen-devel@lists.xenproject.org References: From: Christophe Leroy Content-Language: fr-FR In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Stat-Signature: tqmtxigea56o5k8attd9wa954fccb9in X-Rspam-User: X-Rspamd-Queue-Id: CAA7F180006 X-Rspamd-Server: rspam05 X-HE-Tag: 1755198347-980825 X-HE-Meta: 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 uWON8akt 9GbLjlb6txYdEntqT099HAxYjBT5eFvLegw2tLzLdMbaQZ/QrPc/GQxeQ0XrXaiyCuiwAd8m6S6jNOOe6ynmLzSicR7MK2ahHqixDg3Ym5G2xfzLEq/3KzAdyfrgC/jNcYNKfxUq4fO9B12PQVVIGXkB5iWO/2/EUdBfnWtpkxK9Xlmwlg2LKF5wGpK3UkfFzbUkthmxEf5+bQpGBt0zkHj3YSO7fXAB02PM2LPk3vzr8vwMwin7sgv4N+X6u8Mj9QP/3XNTGO1S1O+6p2nq5VQHNMEmhs6OUYhVUhAOilp2rxgtQHoqyPQfcqQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Le 14/08/2025 à 19:53, Leon Romanovsky a écrit : > Changelog: > v3: > * Fixed typo in "cacheable" word > * Simplified kmsan patch a lot to be simple argument refactoring v2 sent today at 12:13, v3 sent today at 19:53 .... for only that ? Have you read https://docs.kernel.org//process/submitting-patches.html#don-t-get-discouraged-or-impatient ? Thanks Christophe > v2: https://lore.kernel.org/all/cover.1755153054.git.leon@kernel.org > * Used commit messages and cover letter from Jason > * Moved setting IOMMU_MMIO flag to dma_info_to_prot function > * Micro-optimized the code > * Rebased code on v6.17-rc1 > v1: https://lore.kernel.org/all/cover.1754292567.git.leon@kernel.org > * Added new DMA_ATTR_MMIO attribute to indicate > PCI_P2PDMA_MAP_THRU_HOST_BRIDGE path. > * Rewrote dma_map_* functions to use thus new attribute > v0: https://lore.kernel.org/all/cover.1750854543.git.leon@kernel.org/ > ------------------------------------------------------------------------ > > This series refactors the DMA mapping to use physical addresses > as the primary interface instead of page+offset parameters. This > change aligns the DMA API with the underlying hardware reality where > DMA operations work with physical addresses, not page structures. > > The series maintains export symbol backward compatibility by keeping > the old page-based API as wrapper functions around the new physical > address-based implementations. > > This series refactors the DMA mapping API to provide a phys_addr_t > based, and struct-page free, external API that can handle all the > mapping cases we want in modern systems: > > - struct page based cachable DRAM > - struct page MEMORY_DEVICE_PCI_P2PDMA PCI peer to peer non-cachable > MMIO > - struct page-less PCI peer to peer non-cachable MMIO > - struct page-less "resource" MMIO > > Overall this gets much closer to Matthew's long term wish for > struct-pageless IO to cachable DRAM. The remaining primary work would > be in the mm side to allow kmap_local_pfn()/phys_to_virt() to work on > phys_addr_t without a struct page. > > The general design is to remove struct page usage entirely from the > DMA API inner layers. For flows that need to have a KVA for the > physical address they can use kmap_local_pfn() or phys_to_virt(). This > isolates the struct page requirements to MM code only. Long term all > removals of struct page usage are supporting Matthew's memdesc > project which seeks to substantially transform how struct page works. > > Instead make the DMA API internals work on phys_addr_t. Internally > there are still dedicated 'page' and 'resource' flows, except they are > now distinguished by a new DMA_ATTR_MMIO instead of by callchain. Both > flows use the same phys_addr_t. > > When DMA_ATTR_MMIO is specified things work similar to the existing > 'resource' flow. kmap_local_pfn(), phys_to_virt(), phys_to_page(), > pfn_valid(), etc are never called on the phys_addr_t. This requires > rejecting any configuration that would need swiotlb. CPU cache > flushing is not required, and avoided, as ATTR_MMIO also indicates the > address have no cachable mappings. This effectively removes any > DMA API side requirement to have struct page when DMA_ATTR_MMIO is > used. > > In the !DMA_ATTR_MMIO mode things work similarly to the 'page' flow, > except on the common path of no cache flush, no swiotlb it never > touches a struct page. When cache flushing or swiotlb copying > kmap_local_pfn()/phys_to_virt() are used to get a KVA for CPU > usage. This was already the case on the unmap side, now the map side > is symmetric. > > Callers are adjusted to set DMA_ATTR_MMIO. Existing 'resource' users > must set it. The existing struct page based MEMORY_DEVICE_PCI_P2PDMA > path must also set it. This corrects some existing bugs where iommu > mappings for P2P MMIO were improperly marked IOMMU_CACHE. > > Since ATTR_MMIO is made to work with all the existing DMA map entry > points, particularly dma_iova_link(), this finally allows a way to use > the new DMA API to map PCI P2P MMIO without creating struct page. The > VFIO DMABUF series demonstrates how this works. This is intended to > replace the incorrect driver use of dma_map_resource() on PCI BAR > addresses. > > This series does the core code and modern flows. A followup series > will give the same treatment to the legacy dma_ops implementation. > > Thanks > > Leon Romanovsky (16): > dma-mapping: introduce new DMA attribute to indicate MMIO memory > iommu/dma: implement DMA_ATTR_MMIO for dma_iova_link(). > dma-debug: refactor to use physical addresses for page mapping > dma-mapping: rename trace_dma_*map_page to trace_dma_*map_phys > iommu/dma: rename iommu_dma_*map_page to iommu_dma_*map_phys > iommu/dma: extend iommu_dma_*map_phys API to handle MMIO memory > dma-mapping: convert dma_direct_*map_page to be phys_addr_t based > kmsan: convert kmsan_handle_dma to use physical addresses > dma-mapping: handle MMIO flow in dma_map|unmap_page > xen: swiotlb: Open code map_resource callback > dma-mapping: export new dma_*map_phys() interface > mm/hmm: migrate to physical address-based DMA mapping API > mm/hmm: properly take MMIO path > block-dma: migrate to dma_map_phys instead of map_page > block-dma: properly take MMIO path > nvme-pci: unmap MMIO pages with appropriate interface > > Documentation/core-api/dma-api.rst | 4 +- > Documentation/core-api/dma-attributes.rst | 18 ++++ > arch/powerpc/kernel/dma-iommu.c | 4 +- > block/blk-mq-dma.c | 15 ++- > drivers/iommu/dma-iommu.c | 61 +++++------ > drivers/nvme/host/pci.c | 18 +++- > drivers/virtio/virtio_ring.c | 4 +- > drivers/xen/swiotlb-xen.c | 21 +++- > include/linux/blk-mq-dma.h | 6 +- > include/linux/blk_types.h | 2 + > include/linux/dma-direct.h | 2 - > include/linux/dma-map-ops.h | 8 +- > include/linux/dma-mapping.h | 33 ++++++ > include/linux/iommu-dma.h | 11 +- > include/linux/kmsan.h | 9 +- > include/trace/events/dma.h | 9 +- > kernel/dma/debug.c | 71 ++++--------- > kernel/dma/debug.h | 37 ++----- > kernel/dma/direct.c | 22 +--- > kernel/dma/direct.h | 52 ++++++---- > kernel/dma/mapping.c | 117 +++++++++++++--------- > kernel/dma/ops_helpers.c | 6 +- > mm/hmm.c | 19 ++-- > mm/kmsan/hooks.c | 7 +- > rust/kernel/dma.rs | 3 + > tools/virtio/linux/kmsan.h | 2 +- > 26 files changed, 306 insertions(+), 255 deletions(-) >